Cruciate ligament degeneration or rupture is a common canine disease. The cruciate ligaments are the primary stabilizing structures of canine stifle joint. The canine stifle joint is condylar synovial joint. The primary motion of joint is flexion and extension. The three major muscles comprising the caudal thigh group are the biceps femoris, the semitendinosus and the semimembranosus, also collectively known as the hamstring muscles. The bones, muscles, tendons, ligaments etc. of the canine stifle joint are shown in detail in FIGS. 1-6 (Reference: Carpenter, D. H. et al, Mini Review of Canine Stifle Joint Anatomy, Anat. Histol. Embryol., 29, 321-329, 2000).
A cranial view of the left stifle showing associated ligaments and structures is shown in FIG. 1. The following features are identified: 1A, femoral trochlea; 2A, lateral ridge of femoral trochlea; 3A, tendon of long digital extensor; 4A, tendon of popliteus; 5A, lateral collateral ligament; 6A, lateral meniscus; 7A, tibial tuberosity; 8A, patellar ligament; 9A, patella; 10A, parapatellar fibrocartilage; 11A, intermeniscal ligament; 12A, medial meniscus; 13A, medial collateral ligament; 14A, cranial cruciate ligament; 15A, caudal cruciate ligament; 16A, medial ridge of the trochlea.
A caudal view of the right stifle showing associated ligaments and structures is shown in FIG. 2. The following features are identified: 1B, cranial cruciate ligament; 2B, lateral collateral ligament, 3B, lateral meniscus; 4B, cranial ligament of the fibular head; 5B, caudal ligament of the fibular head; 6B, fibula; 7B, caudal meniscotibial ligament of the lateral meniscus; 8B, caudal cruciate ligament; 9B, medial meniscus; 10B, medial collateral ligament; 11B, meniscofemoral ligament.
A lateral view of the right stifle showing associated ligaments and structures is shown in FIG. 3. The following features are identified: 1C, popliteus tendon; 2C, lateral collateral ligament; 3C, sesamoid; 4C, lateral femoropatellar ligament; 5C, quadriceps muscle group tendon of insertion; 6C, patella; 7C, patellar ligament; 8C, lateral meniscus; 9C, tibial tuberosity; 10C, tibial crest; 11C, long digital extensor tendon of origin; 12C, cranial ligament of fibular head; 13C, fibula; 14C, tibia; 15C, os femoris.
A medial view of the right stifle showing associated ligaments and structures is shown in FIG. 4. The following features are identified: 1D, os femoris; 2D, medial femoropatellar ligament; 3D, sesamoid; 4D, medial collateral ligament; 5D, popliteus tendon of origin; 6D, cranial ligament of the fibular head; 7D, fibula; 8D, tibia; 9D, tibial crest; 10D, tibial tuberosity; 11D, patellar ligament; 12D, medial meniscus; 13D, patella; 14D, quadriceps muscle group tendon of insertion.
A medial view of the left pelvic limb muscles and associated structures is shown in FIG. 5. The following features are identified: 1E, cranial sartorius; 2E, caudal sartorius; 3E, cranial tibial; 4E, deep digital flexor; 5E, tibia; 6E, common calcanean tendon; 7E, superficial digital flexor; 8E, gastrocnemius; 9E, biceps femoris tendon of insertion; 10E, semitendinosus, 11E, gracilus; 12E, pectineus; 13E, vastus medialis; 14E, adductor magnus et brevis; 15E, semimembranosus.
A lateral view of the right pelvic limb muscles and associated structures is shown in FIG. 6. The following features are identified: 1F, middle gluteal; 2F, tensor fasciae latae; 3F, cranial sartorius; 4F, vastus lateralis; 5F cranial tibial; 6F, gastroenemiius; 7F, superficial digital flexor; 8F, long digital extensor; 9F, common calcanean tendon; 10F, biceps femoris tendon of insertion; 11F, caudal head of biceps femoris; 12F, cranial head of biceps femoris; 13F, semitendinosus; 14F, semimembranosus; 15F, superficial gluteal.
The cranial cruciate ligament (CrCL) prevents cranial tibial translation or the tibial forward thrust, limits excessive internal rotation of the tibia and prevents hyper extension of the stifle. During the stance phase (weight bearing phase) of the gait cycle, loading of the stifle joint leads to a ventrally directed compressive force, and a horizontally directed force, or a cranial tibial thrust. In an intact stifle, the CrCL resists this force, minimizing any cranial translation of the tibia. In a CrCL deficient stifle, the lack of the stabilizing force, leads to cranial translation of the tibia during the weight bearing phase of the gait cycle. The translation of the tibia during the stance phase can alter the load distribution within the stifle joint, leading to pain, stiffness and osteoarthritis of the joint.
Common surgical treatment options for cruciate ligament disease are Tibial Plateau Levelling Osteotomy (TPLO) and Tibial Tuberosity Advancement (TTA). In a TPLO surgery, illustrated in FIG. 7, a semi-circular cut is made on the dorsal end of the tibia. The tibial articular surface is then rotated and stabilized using bone plates and screws. By levelling the tibial plateau, cranial slippage of the tibia during the stance phase is prevented. In a TTA surgery, illustrated in FIG. 8, the attachment site of the patellar tendon to the tibia is moved forward by cutting the tibial tuberosity and repositioning it with bone plates and screws.
TPLO and TTA both carry a risk of failure due to poor bone healing after the osteotomy, as well as a risk of failure due to fracture of the bone weakened by the osteotomy. Moreover, these surgeries require significant pain management following surgery and entail long recovery times.